Unfortunately Cura 14.09 in my Debian Jessie/sid is not able to detect and communicate with Replicator2X over serial port (ttyACM0). Then I decided to “Save GCode …” and then convert this saved myfile.gcode to myfile.x3g that can be read by Replicator2X from SD Card.

$ gpx -g -m r2x myfile.gcode myfile.x3g

It “barely workes”. I noticed the object is printed more to right side of build bed. Then my suggestion is to put the object more to left side of Cura bed before saving the gcode file.

Conclusion: this approach is not mature enough, but could work if you really care about using only open-source software to control your Makerbot Replicator 2X.